Energy band schematic of a dual junction tandem cell including tunnel junctions (doping p⁺⁺ and n⁺⁺); V_mp(1,2) denote the photovoltage at the maximum power point of the respective absorbers, i.e. the QFL splitting in that component, V$wc$, V$wa$ are the cathodic and anodic working potentials at the given photocurrent (see text).